Global Cloud Cover and Earth Surface Temperature

Abstract

Global mean cloud cover ? and surface temperature T are not independent and must satisfy the requirement of global energy balance, i.e., that the absorbed solar radiation must equal the loss to space of longwave radiant energy. Values of their ?full? differentials with respect to the solar constant (d?/dR0 and dT/dR0) are obtained using simple energy balance considerations and a qualitative concept from a model of the growth and dissipation of cloud systems. The values are +0.009 and +0.35K for a 1% increase in solar constant. Previous solutions for the partial differential |?T/?R0|? are of the order 1?1.5K per 1%. The present results are highly speculative since they involve feedback only to cloud amount and not, for instance, to such things as cloud height or cloud character. However they are supported by the observed change of about 5% in global cloud cover between the times of maxima and minima in the annual cycle of sun-earth distance.